The Walmart.com and pickup/delivery division on their website is not a thing anymore. They seem to be testing a new beta version of the website, and I got to try it yesterday. I have Walmart plus and this is how it went:
One seamless search option, no pickup/delivery and Walmart.com options. I added everything, including groceries and other non groceries to my cart. I selected delivery. Some items were not available in my local store but it didn't matter. Walmart automatically divided my order into two parts, where it decided to ship me some of the things I ordered (chips and club soda) that weren't available at my local store. It was definitely great experience and the UI was clean. I didn't get any out of stock errors at checkout too. Can't wait to use it full time.
The only reason I use Walmart is that I don't trust the products from Amazon anymore, even when they are sold by Amazon. I once ordered shampoo sold my Amazon that was obviously fake, and then I searched around and realized Amazon has a program where they gather the products from different sellers and put it in one huge bin and call all of them sold by Amazon.com